Techniques of inkjet printing that were originally developed for deposition of ink on substrates to created printed text or graphics have been applied to additional applications. As one example, inkjet printing techniques have been applied to depositing metallic conducting material on surface of semiconductor substrates. Thus, for example, inkjet printing techniques may be applied to deposit electrical connections on semiconductor-based electronic devices, such as photovoltaic cells for solar electrical power generation.
A printing head of an inkjet printer typically includes a large plurality of nozzles through which the printing fluid (e.g. ink) may be dispensed. The nozzles are typically arranged in the form of a one- or two-dimensional array. An array of nozzles typically includes rows or lines of aligned nozzles.
For at least some applications of inkjet printing techniques, a nozzle of the array may be expected to be aligned with other nozzles of the array. Thus, each nozzle used in the application may be expected to deposit printing fluid with a particular spatial relationship relative to printing fluid that is deposited by other nozzles used in the application. An example of such an application may include depositing a line of conducting material on a surface of a semiconductor. In order that the line of conduction material have a desired thickness, relative motion between a printing head and the substrate may be in a direction parallel to a row of nozzles of the array. During the course of the motion, a plurality of nozzles of the row may deposit conducting material in a synchronized manner on the surface. Due to the motion, the material that is deposited by each nozzle may be in the form of a printed line of conducting material. It is expected in this case that each of the nozzles of the row (except the first) deposits a line or a layer of conducting material on top of the previously deposited lines were deposited by the previous nozzles. Failure to do so consistently and accurately may reduce the quality of the deposited lines of conducting material.
It is an object of embodiments of the present invention to provide for evaluation of nozzles of a printing head so as to ensure that the printing heads deposits material as part of a printing application in a consistently aligned manner.
It is further object of embodiments of the present invention to provide for evaluation of the nozzles using a reusable substrate.
Other aims and advantages of the present invention will become apparent after reading the present invention and reviewing the accompanying drawings.